The present invention relates generally to integrated circuits. More specifically, the invention relates to enclosing integrated circuits.
U.S. patent application Ser. No. 09/006,759 entitled xe2x80x9cA Semiconductor Wafer Having A Bottom Surface Protective Coatingxe2x80x9d, by Kao et al., filed on Jan. 14, 1998 discloses providing a protective coating on a bottom surface of a semiconductor die. According to the application, a wafer for flip-chips or surface mount dice is coated on a back side with an epoxy and cured. One of the features of the protective coating is to provide protection from light induced bias. Such a protective coating does not cover the side of a die. Processing of surface mount dice may make it difficult to provide a protective coating that is opaque.
The micro surface mount die is an extension of flip chip technology where solder bumps on die pads are the means to make electrical connections between the die and a PC board. Thus the micro surface mount die (SMD) is a true chip size package where the die is the package.
Micro SMD wafers go through normal wafer fabrication processes except that the die pads are redistributed to create a standard pattern of the bumps. Bumps are then provided on the die pads. After the bumping process is completed, the back of the wafer may be coated with epoxy and cured. The wafer may then be singulated.
To facilitate discussion, FIG. 1 is a cross sectional view of a singulated micro surface mount die 10 with a bottom surface coating 12. Solder balls 14 have been mounted to the top side.
It would be desirable to provide protection from light induced bias to the sides of the semiconductor die. In addition, it would be desirable to provide protection from light induced bias, which is opaque to light.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, a variety of techniques is provided for providing protective coverings over a plurality of dice. Generally, dice are formed with an active top side and a bottom side opposite the top side. Enclosures are also formed. The dice are placed in the enclosures so that the bottom side of each die is adjacent to the bottom of an enclosure.
In another embodiment of the invention, a die, and an enclosure covering the bottom side and most of the side surface of the die with adhesive between the die and the enclosure is provided.